function addWaterMarker(str, parentNode, font, textColor) {
  // 水印文字，父元素，字体，文字颜色
  const can = document.createElement('canvas')
  parentNode.appendChild(can)
  can.width = 200
  can.height = 150
  can.style.display = 'none'
  const cans = can.getContext('2d')
  cans.rotate((-20 * Math.PI) / 180)
  cans.font = font || '16px Microsoft JhengHei'
  cans.fillStyle = textColor || 'rgba(180, 180, 180, 0.1)'
  cans.textAlign = 'left'
  cans.textBaseline = 'middle'
  cans.fillText(str, can.width / 10, can.height / 2)
  // parentNode.style.backgroundImage = 'url(' + can.toDataURL('image/png') + ')'

  const div = document.createElement("div");
  div.id = 'watermark';
  div.style.pointerEvents = "none";
  div.style.top = "0px";
  div.style.left = "0px";
  div.style.position = "fixed";
  div.style.zIndex = "100000";
  div.style.width = document.documentElement.clientWidth + "px";
  div.style.height = document.documentElement.clientHeight + "px";
  div.style.background =
    "url(" + can.toDataURL("image/png") + ") left top repeat";
  document.body.appendChild(div);
}

export default {
  mounted: function (el, binding) {
    addWaterMarker(binding.value.text, el, binding.value.font, binding.value.textColor)
  },
}

